New York City introduced a set of planning tools on 25 June 2026 aimed at expanding housing options in historic districts while maintaining landmark protections.
Mayor Zohran Kwame Mamdani and Landmarks Preservation Commission Chair Lisa Kersavage present the initiative as part of a broader effort to support small-scale residential development and better use existing development rights on landmarked properties.
The initiative provides updated resources for Ancillary Dwelling Units (ADUs) and Landmark Transferable Development Rights (TDRs). A new searchable map identifies where ADUs may be added within historic districts, alongside updated fact sheets and guidance materials.
A dedicated support team within the Landmarks Preservation Commission has been established to help property owners navigate application requirements and approvals.
For landmarked buildings, revised TDR guidance explains how unused development capacity can be transferred to other sites in exchange for financial returns that can support maintenance and preservation.
The changes build on 2024 zoning reforms under City of Yes for Housing Opportunity, which allowed more ADUs across much of the city but added extra rules for historic districts.
The Department of Housing Preservation and Development and the Department of Buildings are also involved in implementation through the ADU for You program.
The measures are intended to address housing shortages in neighborhoods where preservation rules often restrict new construction, while also providing financial mechanisms to support the upkeep of historic properties. The approach is designed to integrate housing growth into established communities rather than concentrating it in newly developed areas.
The rollout combines digital mapping tools, clearer application guidance and proposed administrative adjustments at the Landmarks Preservation Commission. These include expanding the range of applications eligible for staff-level review, which would reduce the number requiring full commission hearings and could shorten approval timelines.
Property owners can begin using the ADU map and TDR guidance immediately to assess eligibility and application requirements. Additional procedural changes are under consideration that could further streamline approvals as implementation continues.
